Fiber optic network design is a subset
of a project. That venture may be a major
building project or just the cabling being
planned. But the project needs a manager who works with the team to create
a scope of work that defines the goals of
the entire project. Then the designer can
start working.

Fiber optic network design is not simply sitting down with a CAD program
and laying out cable routes for either
outside plant (OSP) or premises cabling
systems. It’s a lot more than knowing
how to use software. The fiber optic
network designer needs to have a broad
knowledge of fiber optics and several
other topics from communications systems to geology and codes.

A fiber optic network design begins
with the communications requirements.
Is the system an OSP link for a telecom
or internet carrier, or is it a grid management system for an electrical utility?
Is it cabling for a metro network for city
communications, traffic management
and security CCTV cameras? Maybe
it’s premises cabling for a local area
network or a mega data center.

Every system is different and requires
different design approaches. The
designer must understand the needs of
the network user and be able to translate
that into a cable plant design.

Understanding the physical route ofthe network cabling is one of the mostimportant parts of the design process.A site visit is absolutely necessary tounderstand the route the cable musttake and the obstacles in its way. Out-doors, it means driving and walkingthe entire route, taking pictures alongthe way to document the physical envi-ronment the cable plant will take. Asmartphone or a digital camera withgeographic location recording is yourbest tool here.

Underground cables will require documenting where conduit and manholes
already exist and where trenching is
necessary. If there is any question about
the soil conditions for trenching, a geologic survey may be necessary. Locations
of poles and pole ownership need to be
established if aerial cable is planned.

Access to poles is another thing to
note. I’ve been working with a rural electrical co-op on an aerial fiber project, and
finding locations for splice closures in
the mountains and desert was only possible by following current electrical lines.

Choosing components is another
important task for the fiber optic network designer. Correct choices will
make the project easier and cheaper
without compromising quality, but
making those choices means having
knowledge and experience with these
kinds of components. The designer
should get input from others beyond
salesmen, such as experienced contractors that have worked with them
before on successful projects. Contractors always have opinions on what
works best based on their experience.
Be wary of unfamiliar new products.
Look for references to satisfied users
and contractors before committing to
something unknown.

Now is the time to start working ona project schedule. Usually the scope ofwork will include a timeline for finish-ing the project, but the designer needsto survey the site, design the route andhave most of the actual cable plant designdone before the schedule can be updatedbased on component deliveries and real-istic installation times.

If the project goes out for bids, the
design must be complete and the project scheduled for bids to be realistic. If
it’s a design/build project, the designer
will work closely with the contractor (or maybe for the contractor) to
finalize details. If it’s open bids, the
designer should be part of the group
evaluating bids.

This is where things can get busy.
Components need to be ordered. The
proper construction equipment needs
to be scheduled. Planning for storage of
delivered components can be forgotten.
The electrical co-op I have been working with found it needed to clear one of
its storage buildings to make room for 60
miles of fiber optic cable, which came on
15 4-foot wooden reels!

Keep documentation up to date and
do a final review before installation
begins. Details such as the test plan—the
requirements for testing and documenting the results—need to be completed.
The final documentation should show
where the cables run, photos at every
splice location or other work site, where
every fiber in every cable is connected
and what were the final test results.

We’re about ready to begin installation, so the project responsibility falls
on the project manager. I’ll cover that
next month.

Design for LivingFiber optic network design

LAST MONTH, I discussed the growing pains I have
seen in fiber optics. Some of the problems have
been issues with incompetent subcontractors, but
poor network design seems to cause just as many
issues. Why is that?

HAYES is a VDV writer and educator and the president of the Fiber Optic Association. Findhim at
www.
JimHayes.com. I S TOCK/NO_LIMIT_PICTURES